A variety of electronic devices, such as electronic scales, electronic balances, digital sensors and automatic control devices, are used in various industries. These electronic devices can include a device carrier, printed circuit board, cables and so on. In use of some electronic devices, when the electronic devices are powered on, it is desirable to know any power interruption duration of the devices, for diagnosis of an initial state of the devices at power on and compensation for thermal deformation error, or for preheat compensation of the electronic devices during a period after power on. It can be much more important to record the power interruption duration of the electronic devices, such as in a situation where the devices are subjected to power interruption and power on frequently.
A known method of recording power interruption duration is to employ a RTC (Real Time Clock) to record the power interruption duration. There are two kinds of RTC: one is a battery-powered disposable RTC, and the other is a rechargeable RTC (or named “Super capacitor”) which can be reused many times.
Aspects of a RTC (Real Time Clock) in recording power interruption duration include:                1) Complexity and cost of the circuit is increased, because an RTC involves coordination of external circuits;        2) When recording the power interruption duration, a RTC writes point-in-time data into a non-volatile memory continuously, which affects the capacity and read-write lifespan of the non-volatile memory; once the non-volatile memory does not work, the RTC would lose its timing function;        3) Performance of the electronic device can be affected due to high power consumption during recharging of the RTC;        4) Discharge time of the RTC can be limited, and when the RTC runs out of battery, it no longer has timing function; and        5) When an RTC works at a low voltage, timing thereof can be inaccurate, which is less reliable.        